Various technologies have been developed for changing configurations or activities of an information processing device in accordance with conditions.
For example, there exists a technology of dynamically adding a device such as a CPU (a Central Processing Unit) or a memory to an information processing device, or dynamically deleting a device from an information processing device while the information processing device is running. Such a technology is called a “hot-plug”. Dynamic addition or deletion of a device to and from the information processing device by using the hot-plug function is performed in accordance with a load of the information processing device in some cases or it is performed in accordance with a command input from a user in other cases.
The dynamic addition and deletion of the device by using the hot-plug function may also be called “hot-add” and “hot-remove”, respectively. Although in some cases hot-add is called “hot-plug” and hot-remove is called “hot-unplug”, a technology that includes hot-add and hot-remove is called “hot-plug” herein.
Further, in a battery-powered device, a control may sometimes be performed in accordance with a remaining battery capacity. For example, an operating system may sometimes control the power supply to the device or the operating frequency of the device, in accordance with a predetermined policy and remaining battery capacity.
With regard to the battery-powered device, suppressing electrical energy consumption leads to an improved convenience for a user. Accordingly, various technologies for suppressing the electrical energy consumption have been suggested.
Further, many of the battery-powered information processing devices have a function of displaying remaining battery capacity. Various suggestions have been made for a timing of updating the display of the remaining battery capacity or a method for displaying the remaining battery capacity more accurately.
For example, the following technology has been suggested for the information processing device that executes a plurality of programs.
The information processing device has a storage means, a detection means, an acquisition means, and an execution means. The storage means stores state information that is set by a first program and call-back information that is set by a second program by associating them with each other. The detection means detects a change in the state information set by the first program. The acquisition means acquires the call-back information set by the second program, when the detection means detects that the state of the first program has been changed. The execution means calls a call-back on the basis of the call-back information.
For example, the storage means may store information of a battery level as the state information, and may store a program that reports the battery level, as the call-back information. In this case, the execution means may report the battery level on the basis of the call-back information.
Further, various technologies have been suggested for suppressing the electrical energy consumption. For example, a battery may sometimes die because processing of terminating application software that is executed by a virtual machine function has been forgotten. For the purpose of preventing the dying of the battery as mentioned above, a mobile terminal as described below has been suggested.
A touch sensor unit is provided in the mobile terminal. The touch sensor unit is capable of sensing that the user touches the mobile terminal.
When a contact signal is output from the touch sensor unit to a control unit, it is determined that the mobile terminal is being used by the user. On the other hand, when a non-contact signal is output, it is determined that the mobile terminal is not being used at present.
When the non-contact signal is output from the touch sensor unit while the application software is being executed on the mobile terminal, the control unit suspends the execution of the application software that is being executed. With this suspension, the electrical energy consumption of the mobile terminal is suppressed.
Further, a virtual machine system as described below has also been suggested so as to suppress the electrical energy consumption of the virtual machine system for each virtual machine.
In the virtual machine system, a virtual battery management unit provides a virtual battery to a virtual machine. The virtual battery management unit sets an electrical energy consumption policy that indicates electrical energy consumption of the virtual machine system, an amount of charge policy that indicates an amount of charge in the virtual machine, and an electrical energy allocation table that indicates an allocated ratio of the electrical energy allocated to the virtual machine.
A schedule management unit allocates a resource to the virtual machine. In the virtual machine system, a resource quota for the virtual machine is acquired from a resource quota management unit.
When the virtual machine is in operation, processing of converting a CPU time into a discharged amount in reference to the electrical energy consumption policy and the electrical energy allocation table to reduce the remaining capacity of the virtual battery is performed. On the other hand, when the virtual machine is being stopped, processing of converting a stopping time into an amount of charge in reference to the amount of charge policy and the electrical energy allocation table to increase the remaining capacity of the virtual battery is performed.
Some documents as follows have been known.                Japanese Laid-open Patent Publication No. 2008-234494        Japanese Laid-open Patent Publication No. 2007-221228        Japanese Laid-open Patent Publication No. 2010-33207        Mwaikambo, Z., Raj, A., Russell, R., Schopp, J., and Vaddagiri, S., “Linux Kernel Hotplug CPU Support”, Proceedings of the Linux Symposium, 2004, Vol. 2, pp. 467-480 (Linux is a registered trademark)        